What Is Hydrophobia?

Overview

While the term "phobia" might sound like a sophisticated synonym for fear to the average person, it represents something distinct. A phobia goes beyond mere fear; it denotes an intense aversion to something, to the extent that an individual might resort to violence to avoid the object of their phobia. Hydrophobia is a condition with a history deeper than most, and it was historically used as another name for rabies, a disease that famously induces such a severe aversion to water that it causes throat closure. 

Rabies is an extremely severe condition, with a 100% mortality rate once symptoms manifest. As a result, concerted efforts within the global medical community have led to a significant reduction in its prevalence. Read on to learn more about why rabies is so perilous, the hydrophobia it triggers, and how informed citizens can contribute to reducing the spread of this condition while safeguarding themselves.

The term “hydrophobia” can be dissected into two parts: the prefix “hydro-“ pertains to water, and the suffix “-phobia” refers to fear or aversion. Therefore, hydrophobia can represent either a psychological or a physical fear or a profound aversion to water. 

Hydrophobia vs aquaphobia 

There are two terms commonly used to describe a fear of water: hydrophobia and aquaphobia. In contemporary literature, aquaphobia is typically used to denote an extreme and irrational fear of water, often stemming from a traumatic experience, causing the affected person to panic when exposed to bodies of water. An aquaphobic individual might avoid baths, pools, and lakes. This is considered a specific phobia and is fundamentally an anxiety disorder. 

Conversely, hydrophobia was historically used interchangeably with rabies, a disease caused by the lyssavirus. One of the late-stage symptoms of rabies is muscle spasms when the patient encounters water through sight, sound, or taste. Consequently, individuals infected with rabies tend to avoid water.¹

Causes and transmission of hydrophobia

Cause of hydrophobia rabies

Hydrophobia manifests as a late-stage symptom of rabies. It is a zoonotic condition (a condition passed on to a human by an animal, for example, Plague and Lyme Disease). It is a condition caused by the Rabis lyssavirus and affects the central nervous system. It is usually spread by bites and scratches from infected animals like bats and domestic dogs. 

Once clinical symptoms of rabies surface, the disease is almost 100% fatal, so vaccination upon suspected exposure is key. 

There are two subclasses of rabies:

1. Furious Rabies accounts for 80% of all cases, and symptoms include hyperactivity, aggressive behaviour, hallucinations and lack of coordination. Hydrophobia is a symptom of this type of rabies. 
2. Paralytic Rabies accounts for 20% of the cases, where muscles slowly become paralysed, starting at the wound site.

Furious Rabies is the main subtype which has led to the popular characterisation of hydrophobia. The exact cause of hydrophobia is a type of spasm in the pharynx termed paroxysmal contractions.² 

Transmission of rabies 

As mentioned earlier, rabies is a zoonotic disease, and the primary mode of transmission is through deep bites or scratches from animals carrying rabies, typically dogs in 99% of cases.   Contact with the saliva of an infected animal can also result in transmission. In certain regions, such as Australia and Europe, bats pose a significant risk of transmitting rabies.² 

Symptoms of hydrophobia

The main symptom of hydrophobia is described as a dread of water, especially when presented to drink. The person in question may feel thirsty, as seen in patients. However, the contractions in the pharynx (throat) make swallowing difficult. This results in the association of water or any other liquid with the pain the contractions bring.

The fear may increase to the extent that even the sight or thought of water may agitate the patient. When combined with other symptoms of furious rabies, such as hallucinations, decrease in cognitive ability and hyperactivity, the patient may become unstable and violent when given water to drink. This hydrophobia became the defining symptom of rabies, to the point that rabies remains synonymous with hydrophobia to this date.³ 

In a physical examination described in popular research, a patient complained of intense thirst, but any attempt to deliver water caused a hydrophobic spasm. This led to a blockage in the throat, leading the patient to involuntarily repel the glass of water. Tragically, the patient passed on the day of admission. 

Features that are often accompanied by hydrophobia are:

• Fluctuating state of consciousness
• Altered mental state 
• Aerophobia 

The average patient dies 5.7 days after showing symptoms.⁴ 

Diagnosis

 As rabies and, consequently, hydrophobia is fatal once symptoms appear, any bite from a suspected rabid animal is grounds for diagnosis. In cases where the animal is accessible, it may be euthanised, and sections of its brain tissue can be analysed for the presence of the virus.

In most cases, current diagnostic tools are not suitable for detecting a rabies infection before the onset of the disease. However, the disease can be confirmed after clinical diagnosis and post-mortem by a variety of tests, including:

• Saliva Sample analysis
• Skin biopsies 
• Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
• Antibody tests in cerebrospinal fluid and blood serum⁵ 

Treatment and prevention for rabies-induced hydrophobia

As in almost all cases of rabies, after the onset of the disease leads to death, the treatment of rabies and, thus, hydrophobia lies in three frontiers:

Preventative measures 

• If you are a dog owner, make sure your pet is up to date on their rabies vaccinations. The same also applies to cats and ferrets. 
• Make sure your pets are under supervision at all times, as if they get bitten by a rabid animal, they also become vectors.
• Ensure that stray animals are reported to animal control or organisations like the humane society.
• If you’re out hiking, be wary of wild animals 
• Do not stay for extended areas in areas densely populated with bats 
• Wash any animal bites with soap and water 
• If you feel you have been exposed to a possibly rabid animal, contact a General Practitioner (GP) on an urgent basis to get post-exposure prophylaxis (vaccination). Prevention is the only option, so stay vigilant^2,5 

Pre-exposure vaccination

This is also known as Rabies Pre-Exposure Prophylaxis or Rabies PrEP. This vaccination may be taken by people who have occupations that make them more likely than the average person to come into contact with a rabid animal, for example, bat handlers. Many countries have their own set of guidelines as to which workers are advised to get this vaccine and on what schedule. 

You may need Rabies PrEP if you

• Work with live or concentrated rabies virus in laboratories 
• Handle bats frequently or enter environments with many bats, like caves. 
• Are a veterinarian, technician at a veterinary clinic, wildlife biologist, rehabilitator, dog trainer or a trapper 
• If you’re travelling to an area in the world where rabies is commonly found in wild dogs⁶ 

Post-exposure vaccination

This emergency measure, known as Rabies Post-Exposure Prophylaxis or PEP, should be sought immediately upon suspected exposure to rabies. It aids in preventing the virus from infecting the central nervous system, thereby averting symptoms and potential fatality. Consult a general practitioner to obtain PEP as soon as possible if you have been bitten by an animal that may be carrying rabies.  

Summary

Hydrophobia, a fear of water associated with late-stage rabies infection, should not be confused with aquaphobia, which is a psychological fear of water due to traumatic experiences. Hydrophobia is often used interchangeably with rabies in older literature, as it is a prominent symptom. Rabies, a viral zoonotic disease, spreads through bites, scratches, and contact with infected carriers, mainly dogs (99% of cases), with bat transmission also reported. Rabies has two types: paralytic and furious rabies, with hydrophobia a symptom of the latter. Hydrophobic patients experience thirst but develop painful throat spasms upon drinking water, leading to a violent aversion to it. Since rabies is nearly 100% fatal after symptoms appear, prevention is the primary focus.

High-risk occupations, like veterinarians and bat handlers, use Rabies Pre-Exposure Prophylaxis (Rabies PrEP) as a precaution. In cases of suspected exposure to a rabid animal, immediate Post-Exposure Prophylaxis treatment aims to prevent the virus from reaching the central nervous system and causing death.

Pet owners should ensure their pets receive up-to-date rabies vaccinations and avoid contact with potentially infected animals. As rabies is incurable once symptoms manifest, prompt treatment and preventive measures are essential.